Lug cap



E. M. ENKUR' Nov. 8, 1938.

LUG CAP Filed May 5, 1954 2 Sheets-Sheet 2 IIIIIIIIIIIIIIII/ ammed Nov. s, 1938 UNITED STATES PATENT OFFICE LUG CAP Application May 5, 1934, Serial No. 724,152

3 Claims.

This invention relates to lug caps, that is, caps of the type having a plurality of spaced indentations in the skirt thereof and adapted to be rotated into engagement with threads or pro- 6 jections upon the neck of a container to produce the desired seal.

Conventional lug caps are satisfactory but possess structural defects in that difficulty is frequently experienced due to cracking of the 10 threads, for example of a glass container, and breaking or outward wedging of the cap lugs with resultant distortion of the cap. These defects develop under the high sealing pressures required for commercial packaging, for example in vacuum sealing, and destroying the value of the seal.

Lug cap sealing efiiciency depends (1) upon the rigidity of the cap body for-the given thickness of metal used, and (2) upon the flexibility of the sealing bead and cap lugs.

The cap of the present invention is provided with an inwardly opening and outwardly projecting ridge contiguous with the free or open edge portion of the cap which is usually folded or rolled in the form of a bead and in which the container engaging lugs are formed. This ridge possesses a number of advantages in that first, it reinforces the cap diametrically to maintain its roundness and in this respect cooperates with the bottom edge or bead of the cap; second, the ridge being immediately contiguous to the bottom edge or bead in which the lugs are formed, the lugs are flexibly and resiliently hinged upon the ridge; third, the ridge adds elasticity to the skirt so that down-pull strains tending to bulge and distort the cap and skirt or draw the lugs outwardly are effectively absorbed; fourth, the high downward sealing pressure or down-pull strain is uniformly distributed and inequalities in the top sealing surface are overcome without producing a bulging or strain upon the skirt or the container; and fifth, this ridge acts to absorb the strain upon the lugs and the strain upon the glass threads and to distribute the same so that at no point is the pressure abnormal or of such force as to crack the lugs or the glass, notwithstanding that high sealing pressures are used as in vacuum sealing.

When it is considered that packages are provided with lug caps, the contents of which are to be used from time to time, the advantages of a cap which may be continuously removed and replaced without destroying its sealing value and appearance or marring the glass threads of the container, will be readily appreciated.

A further structural feature of the present cap resides in the provision of a sealing bead in the top of the cap which assures an eflicient seal at all times and whereby the cap may be employed with either a minimum or a maximum diameter thread finish without producing bulging of the top or the skirt and without distorting the cap should inequalities be present in the sealing lip of the container. This sealing bead, which renders the top flexible and elastic, cooperates with the circumferential ridge produced in the skirt body and also imparts strength and elasticity to the skirt, as above described, in absorbing the cracking and breaking strains experienced in connection with the cap lugs and the threads or projections of the glass finish. Briefly, (1) the circumferential ridge in the skirt body maintains the shape of the cap diametrically and distributes the down-pull strain uniformly so that it does not reach a breaking tension at any point as regards either the cap lugs or the container finish and flexibly and resiliently supports the lugs, and (2) the sealing head in the top of the cap acts in a similar manner to distribute the down-pull strain. Both of these structural characteristics therefore contribute toward maintaining the cap in its initial shape as the one enhances the effect of the other in reducing any possibility of outward bending of the metal of the top or of the skirt; also the down-pull strain is distributed so that neither the cap lugs are broken or wedged outwardly or the glass threads cracked.

The invention comprises further novel features which will be fully described in the accompanying specification.

Referring to the drawings:

Figure 1 is a top elevation of a hat-shaped blank having my improved sealing bead formed therein.

Figure 2 is a section on the line 22 of Figure 1.

Figure 3 is a top elevation of a cap in a preliminary stage of its manufacture from a hatshaped blank.

Figure 4 is a section on the line 4-4 of Figure 3.

Figure 5 is a sectional view of my improved cap.

Figure 6 is a bottom elevation of the cap shown in Figure 5.

Figure 7 is a side elevation of my improved cap shown in Figures 5 and 6.

Figure 8 is a bottom elevation partly broken away, of a modified form of cap.

Figure 9 is a sectional view partly broken away on the line 99 of Figure 8.

Figure 10 is a side elevation of one form of cap;

Figure 11 is a sectional view partly broken away and showing a cap having a ridge portion and hollow bead; and

Figure 12 is a sectional view partly broken away showing the cap of Figure 11 with one of the lugs thereof in engagement with the thread on a container.

Referring to Figures 1 and 2 of the drawings, I have illustrated a hat-shaped blank having a top H), a skirt II and a rim I2. This blank is suitably stamped from sheets or discs of proper gauge metal and in the forming operation the sealing bead I3 is produced in the top of the cap. This sealing bead is in the form of a concentric groove spaced inwardly from the skirt wall, as shown, having a short side I4 and a long side I5. It will be noted that the long side [5 is inclined at an obtuse angle to the top of the cap toward the skirt and extends to the skirt as in Figure 9, or merges with a marginal area of the top adjacent the skirt, as in Figure 1, forming a substantially continuous arch.

Referring to Figure 5, I have illustrated the complete cap having an offset portion l6 providing a liner seat ll, circumferential knurling l8 extending throughout a substantial height of the skirt, a circumferential inwardly opening and outwardly projecting ridge l9 immediately below the knurling and a rolled bottom edge 20 contiguous to said ridge and in which the lugs 2| are produced.

In the manufacture of the cap, the offset portion l6, knurling l8, ridge l9 and precurling of the rim l2, as shown in Figure 4, are preferably produced as a simultaneous operation. Thereafter the curling of the rim is completed, forming a closed hollow bead 20 in abutting or contacting relation with the ridge [9 and the lugs are pressed in the bead 20 extending radially inward of the skirt as shown in Figures 6, 8 and 9.

In Figures 6 and '7, the head is collapsed upwardly against the ridge l9 and pressed inwardly while in Figures 8 and 9 the bead is collapsed and bent inwardly of the cap by a radial pres-- sure only.

In Figure 11, I have illustrated the head 20 as being oblong or ov'ular in cross-section, with its free end in contact with the lower wall 22 of the ridge IS. The free edge 23 of the bead 20 may extend a greater or lesser distance within the curl as desired.

In the method of manufacturing the cap, the hat-shaped blank of Figure 2 having the sealing bead l3 therein is submitted, as stated, to a single operation for producing the final cap. That is, the precurling of the rim l2, the forming of the ridge l9 in the body of the skirt and the curving of same in cross-section, the knurling operation and the offsetting of the skirt adjacent the top to form a liner seat, are all produced simultaneously during the revolving and rotation of the blank on the chuck in the first segment of its path of revolution. The closing of the curl into a hollow bead and its bending and positioning immediately contiguous to the ridge l9 and parallel and in alignment therewith, i. e., forming the lower portion of the body of the skirt substantially S-shape in cross-section, as shown in Figure 11, is accomplished during the second stage of the revolution and rotation of the blank. In the third stage, the lugs are pressed into the bead 20 at the proper points.

In this manufacturing operation, there is little or no strain upon the metal of the skirt, due to the pressing in of the lugs for the reason that the bead being under the ridge at the end of the second stage and the lower wall of the ridge being curved and extended inwardly, the pressing operation is simply a bending of the metal in the same direction in continuation of the lower wall of the ridge. Heretofore, in pressing in the lugs, they were pressed directly from the bead and necessarily the metal of the adjacent skirt portion is strained and frequently shears directly above the bead at the points of lug formation, due to bending the skirt at an acute or right angle to its vertical plane. Since, however, the curved and inward projection of the lower wall of the ridge constitutes, in efiect, a preformed element, its formation at the time of pressing the lugs is obviated, and hence the metal of the skirt adjacent the lugs is neither strained nor subjected to such a shearing pressure.

I have shown in Figure 10 an enlarged under plan view of the improved cap having a substantially straight side wall or skirt 18, a ridge l9 and bead 20, the ridge and bead projecting substantially the same distance beyond the skirt body and the ridge being disposed in superposed relation to the bead. It will be noted that the lugs 2| are formed in the bead 20.

By reason of the provision of the ridge l9, it is possible for the lugs to accommodate irregularities in the threads of a jar whereby the diametrical shape of the cap is maintained and the downpull strain is uniformly distributed so that it does.

not reach the breaking tension anywhere as regards either the cap lugs or the container finish. In other words, this ridge flexibly and resiliently supports the lugs.

The sealing bead l3 in the top of the cap while not always necessary is in some cases desirable, and further acts in cooperation with the ridge to distribute the down-pull strain.

Both of these structural characteristics aid in maintaining the cap in its initial shape as the one enhances the eifect of the other in reducing any possibility of outward bending of the metal of the top or of the skirt. At the same time, the strain is prevented from so acting upon the glass threads as to crack or sever the same.

Referring to Figure 11, I have illustrated the cap in position upon a jar 24, and in Figure 12 I have illustrated the manner in which the lugs 2| engage the threads 25 of the jar. The cap is provided with the usual cushion liner 26. From these views, it will be understood how the ridge I 0 effectively serves to flexibly and resiliently support the lugs 2| and also the manner in which the sealing bead l3 operates to distribute the downpull strain.

Various modifications may be made in the cap disclosed, and where these fall within the spirit of the invention, they are considered to be comprehended within the scope of the appended claims.

I claim:

1. A cap having a top and a substantially straight downwardly depending skirt, a relatively narrow outwardly projecting circumferential ridge of substantially less area than the skirt body and formed in the skirt body adjacent the free edge thereof, the free edge of the skirt being rolled into a bead, and container engaging lugs pressed in said head.

2. A cap having a top and a substantially straight downwardly depending skirt. a relatively narrow outwardly projecting circumferential ridge of substantially less area than the skirt body and formed in the skirt body adjacent the free edge thereof, the free edge of the skirt being rolled into a. bead, and container engaging lugs pressed in said bead, said ridge and said bead being arranged in superposed relation and projecting substantially the same distance beyond the skirt body.

3. A cap having a top and a substantially straight downwardly depending skirt, said top having a circumferential sealing bead formed therein, a relatively narrow outwardly projecting circumferential ridge of substantially less area than the skirt body and formed in the skirt body adjacent the free edge thereof, the free edge of the skirt being rolled into a bead, and container engaging lugs pressed in said bead, said ridge and said sealing bead acting to maintain the cap in its initial shape and distribute the down-pull strain when the cap is engaged with the threads of a container.

EDWARD M. ENKUR. 

